Apparatus for forming bearing metal surfaces on backing metals



APPARATUS FOR FORMING BEARING METAL SURFACES 0N BACKING METALS c. M. ANGEL Original Filed Nov. 24, 1941 k '2 Mai 6 g m sis rye (LA-4 Patented May 23, 1944 with ATENT OFFICE APPARATUS FOR FORMING BEARING METAL SURFACES ON BACKING METALS 420,210. Divided and 1943, Serial No. 486,903

2 Claims.

This invention relates in general to an improved apparatus for forming bearing surfaces or liners of copper alloys or the like on objects made from a different metal such as cast iron, steel or the like. The present application is a division of my co-pending application Serial No. 10, filed November 24, 1941.

More specifically, the invention as shown herein is directed to an improved apparatus for forming and reconditioning shoe and wedge faces, hub liners, and journal brasses on locomotive driving boxes, by fusing a copper alloy or other suitable nonferrous metal to a backing of ferrous metal. However, it will be understood that the apparatus may be employed for forming and reconditioning other locomotive and railroad car parts and bearings which are used for other purposes.

Heretofore, it has been the practice to form shoe and wedge and hub liners on locomotive driving boxes, by pouring molten bronze on the backing metal and securing the bronze in place by means of tap bolts and dovetail sections in the steel or other ferrous backing material. Considerable difficulty has been experienced in obtaining satisfactory, durable driving boxes when formed in this manner since it has been found that the metal of the bearing surfaces or liners are not fused to the backing metal and the surfaces crack, separate from the backing material during use or become loose around tap bolts and in dovetail sections, making early replacement necessary.

Accordingly, a principal object of the instant invention is the provision of a means whereby the bearing surfaces or liners are made an integral part of the backing metal and an improved union between the two is obtained.

Another important object of the invention is the provision of improved means whereby the liners may be reconditioned by a building up method, this apparatus being used to predetermine the depth to which the bearing metal will be added so that a substantiallyaccurate bearing formation is obtained by a casting process which requires a minimum amount of skill on the part of the operator.

To attain the foregoing object, I have provided herein a system of spillways which permit excessive amounts of molten metal to be applied to the backing metal or to the worn lining metal, these spillways taking away the excess metal when a predetermined thickness is obtained, and transmitting the same to an ingot mold where it is available for remelting.

this application May 13,

I have found that the above recited additive process of forming liners by fusing the same to the backing metal is additionally improved by the application of excessive amounts of molten bearing or liner metal to the backing metal in such a manner that the molten metal flows freely past the surface to which it is to be fused, for a somewhat prolonged period of time, that is throughout the time of the pouring operation. A further important object of the invention is, therefore, the provision of a means for obtaining this prolonged period of flow without necessitating the exercise of great skill on the part of the (operator whereby the liners may be formed easily, rapidly, emciently, and economically.

A further object of the invention is the provision of a means for splitting the hub liner casting to allow for expansion and contraction during the pouring and subsequent cooling of the molten metal, and thus avoid cracking and separation from the backing metal; and also to allow for movement of the driving box under impact in service should strains occur which would cause the liner to crack.

Another object of the invention is the provision in conjunction with the above apparatus, of an improved method of establishing or applying an initial deposit of the bearing alloy on the backing metal to improve the union of the parts.

It will be understood that the apparatus herein described, may .be applied for reconditioning worn bearings or liners as well as for the preparation or forming of entirely new surface beanings, and that where the surface to be covered by the bearing, driving box surface, or like expressions are used, they are directed to either the actual surface of the driving box proper or to the worn surface of old bearings or liners which are being reconditioned.

Numerous other objects and advantages of the invention will be apparent as it is better understood from the following description, which, when taken in connection with the accompanying drawing, discloses a preferred embodiment thereof.

In the drawing,

Fig. 1 is a side elevational view of the apparatus used for forming the shoe and wedge faces on a locomotive drive box;

Fig. 2 is a top plan view of the apparatus shown in Fig. 1;

Fig. 3 is a front elevational view looking toward the right of Fig. 1 with the ingot mold removed.

Referring to the drawing, and more particularly to Figs. 1, 2 and 3 thereof, the preferred apparatus employed for the formation of shoe and wedge liners, on a driving box H is shown. The driving box shown is of standard construction and includes a body i2, attachment flanges l3 and I30. and attachment lugs l4.

Preferably before the bearing parts are cast to the box I I as hereinafter described, the box is so treated as to deposit a film of the bearing alloy to the surfaces thereof. One method of accomplishing this is to place copper or copper alloy turnings upon the surfaces to a depth of to and fuse the same thereto with a carbon are using approximately 587 amperes at 80 volts. It will be understood, however, that the current used may vary widely under varying conditions of operation and of materials being worked upon. Another method is to use a bearing alloy brazing rod and apply the film with an oxyacetylene torch. Another highly satisfactory method is to electroplate a film of bearing metal such as copper orcopper alloy to the surfaces. By so applying a film of the bearing metal to the surfaces, an initial deposit is obtained which is securely fused and united with the driving box surfaces so that the later union of the bearings proper to the driving box H, is facilitated. After this initial layer of bearing metal is formed, the surface thereof is cleansed as by pickling or by bombardment with steel shot, or blasted with an abrasive material, or any other suitable method of cleansing the surface may be employed.

As previously explained, there are two important factors which concern the casting of the bearing metal on the surfaces of the driving box II. First, it is highly desirable that the molten metal be poured in excess of the volume required for the bearing and that the excess metal flow freely past the surface where fusion occurs, thus maintaining the temperature of the surface at that of the molten metal. In using such a method it is of course, necessary that the path of flow of the molten metal be so directed that continuous flow past said surface is obtained throughout the pouring operation and so that the excess metal is properly disposed of without blocking off or damming up the flow. Secondly, it is highly desirable that as the pouring progresses and the approximate dimensions of the desired bearing are reached, further increase of the bearing dimensions cease and that the excess metal poured thereafter be disposed of after passing through the mold cavity. To the end that the above character of fiow be obtained, spillways are provided which have predetermined levels and which afford an exit for the excess of molten bearing metal and at the same time determine the path of flow of the metal and insure fiow past the surface to which the bearing or liner is to be attached.

The general path of flow of the molten metal hereinbefore. described in connection with the previously described bearing surfaces is here applicable. This flow is attained by the use of the strips 44 and 45 which are provided with spillways 44a and 25a respectively. The bottom of each spillway is on a level with the top surface of the liner being cast. When the ladle is manipulated through the path defined by arrows I, J, K, L, M, N and O, the molten bearing metal will be properly distributed to flow from all parts of the cavity out through the spillways 44a and 45a.

These spillways permit the excess metal to flow from the cavity into suitable ingot molds 46 and 41. Due to the configuration of the top portion of the driving box H and the receded position of the spillway 45a, a chute 48 is provided for directing the metal to the ingot mold 41.

It will be seen that by employing the procedure hereinbefore described, the required bearing surfaces have been formed on the driving box I I, and in each case the assembly is such that the flow of molten metal over the fusion surface for a prolonged period of time is insured. Preferably the bearing forming operations are performed in the order described herein.

It is to be understood that the forming operations are preceded by the earlier described formation of the initial thin layer or coating by any preferred or desired method, such as electrodeposition, whereupon the surface is suitably cleaned. This procedure may then be followed by a final fusion heating of the entire driving box H to create a strong union between the various bearing linings and the surfaces of the driving box.

It will be seen that with the apparatus herein described, the bearings will be of uniform and even strength and texture and will be fused to the driving box surfaces throughout their surface area. Furthermore, due to the method employed the bearings will be free from fissures and weak spots where cracking and deterioration may occur.

It will be understood that whenever a bearing surface so applied becomes worn, it can be reconditioned and restored to its original size by employing the apparatus herein described. Care should be taken to have the part to be rebuilt cleaned and preheated to proper temperature before applying additional bearing metal.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the devices mentioned herein without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the forms hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In apparatus for forming shoe and wedge liners on a locomotive driving box or the like, a shoe and wedge liner mold cavity, the shoe and wedge liner surface of the driving box constituting the bottom wall of said cavity, flanges on said driving box, said flanges constituting the side walls of said cavity, strips of fireproof material across the ends of said flanges, said strips constituing the end walls of said cavity, spillways which form a dam for molten metal in said strips, said spillways being adapted to conduct molten bearing metal away from said cavity.

2. In apparatus for forming shoe and wedge liners on a locomotive driving box or the like, an open top shoe and wedge liner mold cavity, the shoe and wedge liner surface of the driving'box constituting the bottom wall of said cavity, means for forming the remaining walls of said cavity,

spillways in the walls of said cavity, theoverfiow level of said spillways being in theplane of the desired surface height of the shoe and wedge liner being formed.

CHARLES M. ANGEL. 

